Sludging inhibited hydrocarbon fuel



United States Patent U.S. CI. 4466 7 Claims ABSTRACT OF THE DISCLOSURE A hydrocarbon fuel containing an additive selected from (1) a mixture of hydrogenated condensation products of reducing sugars and long chain aliphatic amines and (2) aliphatic and aromatic carboxylic acid salts of said mixture of hydrogenated condensation products, said additive being present in an amount sutficient to substantially inhibit sludging of said hydrocarbon fuel.

This application is a division of U.S. patent application, S.N. 251,748, filed Jan. 16, 1963, now abandoned, which in turn is a continuation-in-part of U.S. patent application S.N. 197,263, filed May 24, 1962, now abandoned.

This invention relates to a hydrocarbon fuel containing an additive which functions to inhibit or retard sludging, particularly at temperatures up to 500 F.

Hydrocarbon fuels in general and particularly hydrocarbon fuels obtained from crude oil by thermal and catalytic processes, especially hydrocarbon fuels such as various grades of furnace oils, diesel oils, kerosene and the like, are prone to form a polymeric material which, under normal storage conditions, precipitates and forms a sludge. This effect is termed sludging. This sludge plugs oil lines, burner jets, pumps and filter screens.

Sludging is promoted by an increase in temperature. This presents a serious problem in the case of jet fuels which usually comprise various grades and blends of kerosene and the like. Aircraft flight at supersonic speeds is accompanied by considerable heat generation as a result of air friction, engine heat and operation of equipment such as air conditioning and radar. It has been proposed to dissipate this heat by using the aircraft jet fuel as a heat sink to cool hot equipment and surfaces. For example, under this proposal engine lube oil would be cooled by passing it through a heat exchanger in which the jet fuel functions as a coolant while on its way from the fuel storage tanks to the engine. It is expected that under these conditions the jet fuel will be heated to temperatures up to 500 F. or higher. Hence, unless special steps are taken to prevent this, sludging will take place in the jet fuel with such speed and in such quantity as to rapidly clog fuel filters, fuel lines, heat exchangers and fuel nozzles with possibly disastrous results. Hence, it is imperative that jet fuel under these conditions be stable at temperatures up to 500 F.

This invention is based upon the discovery that hydrogenated condensation products of long chain aliphatic amines and reducing sugars, and aliphatic and aromatic carboxylic acid salts of these hydrogenated condensation products suppress sludge formation in hydrocarbon fuels. In summary, this invention broadly involves a sludging inhibited hydrocarbon fuel composition which comprises a hydrocarbon fuel containing at an effective concentration as an anti-sludging additive a member of the group consisting of hydrogenated condensation products of long chain aliphatic amines and reducing sugars, and

aliphatic and aromatic carboxylic acid salts of these hydrogenated condensation products.

Hydrogenated condensation products of long chain aliphatic amines and reducing sugars, and aliphatic and aromatic carboxylic acid salts of these hydrogenated condensation products are readily made from the condensation products of long chain aliphatic amines and reducing sugars.

The condensation products of long chain aliphatic amines and reducing sugars are known compounds. They and their preparation are disclosed in detail in the U.S. patents, No. 2,808,401 and No. 2,805,340, to Erickson, in the article by Erickson, J. Am. Chem. Soc. 77, 2839 (1955), and in German Patent 1,079,381. Typical examples of a reducing sugar are lactose, glucose, maltose, cellobiose, galactose, mannose and the like with lactose and glucose being preferred. Typical examples of a long chain aliphatic amine, an aliphatic amine having at least 8 carbon atoms, preferably at least 16 carbon atoms, and usually at most about 22 carbon atoms although a larger number can be employed, are such primary amines as octyl'amine, dodecylamine, heptadecylamine, hexadecylamine, octadecylamine, octadecenylamine, octadecadienylamine, N-dodecyltrimethylenediamine, N-octadecyltrimethylenediamine, mixtures of these amines and of various other amines and mixtures of amines derived from natural fats such as tallow, soybeam oil, coconut oil and the like. As far as this invention is concerned, the number of amine substituents in the condensation product molecule can vary. For example, in the case of the condensation product of a long chain aliphatic amine and glucose, the number of amine substituents can be in a range from 1 to 5 with the preferred number of amine substituents being 1-2. In the case of the condensation product of a long chain aliphatic amine and lactose as well as in the case of the condensation product of a long chain aliphatic amine and maltose, the number of amine substituents in the condensation product molecule can be in a range from 1 to 3 with 23 being preferred.

Under the concepts of this invention it is necessary that the condensation products of long chain aliphatic amines and reducing sugars be hydrogenated. The non hydrogenated condensation products generally are unstable under storage conditions and show very little activity as hydrocarbon fuel antisludgin g additives. On the other hand, the hydrogenated condensation products are stable under normal storage conditions and are very active antisludging additives for hydrocarbon fuels and the like.

The hydrogenated condensation products are prepared from the condensation products by hydrogenating the condensation products either in isolated conditions or in their condensation reaction mixtures. Hydrogenation of the condensation products is accomplished by adding hydrogen thereto at a temperature of 100 C. at a pressure of 200-2000 pounds per square inch and in the presence of a hydrogenation catalyst such as Raney nickel. When hydrogenation is complete, the catalyst is removed and the hydrogenated condensation product is preferably isolated and dried.

The aliphatic and aromatic carboxylic acid salts of the hydrogenated condensation products of long chain aliphatic amines and reducing sugars are made in each case by warming a mixture of the carboxylic acid and the hydrogenated condensation product until a homogeneous solution results. Preferred carboxylic acids are those having 4-20 carbon atoms although carboxylic acids having less than 4 or more than 20 carbon atoms can be employed. Examples of suitable aliphatic and aromatic carboxylic acids are such monocarboxylic acids as isobutyric acid, 2-ethylhexoic acid, lauric acid, oleic acid, stearic acid, naphthoic acid and various acids and mixtures of acids derived from natural fats and oils, such as tallow, soybean oil, tall oils and the like. In general, the concentration of the carboxylic acid in .the mixture can vary. Preferably, it is such that the mole ratio of carboxyl groups to amino nitrogens present in the hydrogenated condensation product is about 1:1. Lower and higher concentrations can be used, however.

Concentration of the antisludging additive of this invention in the hydrocarbon fuel composition in general depends upon the degree or extent of sludging inhibition effect desired. This in turn depends upon the hydrocarbon fuel involved as well as the storage and use conditions to which a particular hydrocarbon fuel is to be subjected. In general, the concentration must be at least an effective concentration, that is, a concentration whereat inhibition of sludging under normal conditions is at least substantial. Under most normally encountered conditions a concentration of the antisludging additive in a range from about 0.0005 to about 0.05% by weight of the hydrocarbon fuel is generally satisfactory. This is approximately equivalent to a concentration generally in a range from about 1 to about 100 pounds per 1000 barrels (U.S.) of the hydrocarbon fuel. A concentration of the antisludging additive of this invention in a range from about 0.002 to about 0.05% by weight of the hydrocarbon fuel [approximately equivalent to a concentration in a range from about 5 to about 50 pounds per 1000 barrels (U.S.) of the hydrocarbon fuel] is generally preferred, however. While these ranges are applicable to hydrocarbon fuels in general, the concentration of the antisludging additive of this invention in the case of fuel: oils is usually in a range from about 0.001 to about 0.05 by weight of the fuel oil [approximately equivalent to a concentration in a range from about 2 to about 100 pounds per 1000 barrels (U.S.) of the fuel oil] and preferably in a range from about 0.005 to about 0.02% by weight of the fuel oil [approximately equivalent to a concentration in a range from about to about 50 pounds per 1000 barrels (U.S.) of the fuel oil]. In the case of jet fuels, the concentration of the antisludging additive of this invention is generally in a range from about 0.0005 to about 0.05% by weight of the jet fuel [approximately equivalent to a concentration in a range from about 1 to about 100 pounds per 1000 barrels (U.S.) of the jet fuel] and preferably in a range from about 0.002 to about 0.02% by weight of the jet fuel [approximately equivalent to a concentration in a range from about 5 to about 50 pounds per 1000 barrels (U.S.) of the jet fuel].

The hydrocarbon fuel composition of this invention is prepared merely by admixing the antisludging additive of this invention with the hydrocarbon fuel to be stabilized relative to sludging. The antisludging additive of this invention in general is characterized by good solubility in organic solvents, particularly hydrocarbon solvents, at the concentrations normally employed. In this regard, the carboxylic acid salts of the hydrogenated condensation products have an advantage in that in general they are more soluble in hydrocarbon oils at low temperatures than the hydrogenated condensation products. However, in general, both the hydrogenated condensation products of this invention and the carboxylic acid salts thereof, upon admixture at 20 C. with a hydrocarbon fuel, generally go into solution readily.

This invention is further illustrated by the following examples of various aspects thereof, including specific embodiments of the invention. This invention is not limited to these specific embodiments unless otherwise indicated.

Example 1 This example illustrates the synthesis of a hydrogenated condensation product of lactose and octadecylamine.

36 grams (0.1 mole) of lactose, 81 grams (0.3 mole) of octadecylamine, 400 milliliters of isopropanol and 240 milliliters of water are admixed, heated to a temperature of 6070 C., and maintained at this temperature until a homogenous solution results. The solution is then allowed to cool to room temperature (20 C.) and is kept at this temperature for 24 hours. During this time a precipitate forms. The precipitate is removed by filtration and dried, giving a light tan powder. This powder is a condensation product of lactose and octadecylamine, which product predominates in lactose having three octadecylamine substituents. A typical yield of the product is 108 grams.

100 grams of this condensation product are dissolved in 300 milliliters of warm ethanol and the resulting solution introduced into a suitable autoclave. 5 grams of Raney nickel catalyst are added to the solution in the autoclave. Hydrogen is then introduced into the autoclave at a pressure of 1500-2000 pounds per square inch and the solution heated to a temperature of 100 .C. When no more hydrogen is taken up into the solution, the catalyst is removed'as by filtration from the hydrogenated solution. Then the ethanol is removed from the solution by evaporation, giving a solid product. This solid product is a hydrogenated condensation product of lactose and octadecylamine, which product predominates in a compound having three amine substituents in its molecule.

Example 2 This example illustrates the hynthesis of a hydrogenated condensation product of lactose and octadecenylamine.

The instructions of Example 1 are followed except that in place of 81 grams of octadecylamine, grams of octadecenylamine are used. The resulting hydrogenated condensation product predominates in a compound having three amine substituents in its molecule.

Example 3 This example illustrates the synthesis of a hydrogenated condensation product of lactose and dodecylamine.

The instructions of Example 1 are followed except that in place of 81 grams of octadecylamine, 55.5 grams of dodecylamine are used. The hydrogenated condensation product thus obtained predominates in a compound having three amine substituents in its molecule.

Example 4 This example illustrates the synthesis of a hydrogenated condensation product of lactose and N-(higher alkyl) trimethylenediamines.

The instructions of Example 1 are followed except that instead of 81 grams of octadecylamine, there are used 97.7 grams of a commercial product (Duomeen T) consisting essentially of a mixture of N-(higher alkyl)trimethylenediamines wherein the alkyl groups are beef tallow fatty acid residues. The resulting hydrogenated condensation product predominates in compounds having three amine substituents in their molecules.

Example 5 This example illustrates the synthesis of a hydrogenated condensation product of glucose and octadecylamine.

18 grams (0.1 mole) of glucose, 27 grams (0.1 mole) of octadecylamine, milliliters of water and 200 milliliters of isopropanol are admixed and heated to a temperature of 70-80 C. The mixture is maintained at this temperature until a homogenous solution results. The solution is then allowed to stand at room temperature (20 C.) for 24 hours. During this period of time a precipitate forms. The precipitate is removed from the solution as by filtration, whereby there is obtained a light tan solid. A typical yield of the solid is 35 grams. This solid is a condensation product of glucose and octadecylamine, which predominates in a compound having one octadecylamine substituent in its molecule.

The condensation product of glucose and octadecylamine thus obtained is dissolved in 100 milliliters of warm ethanol and the resulting solution introduced into a suitable autoclave. 5 grams of Raney nickel catalyst are added to the solution in the autoclave. Hydrogen is then passed into the autoclave at a pressure of 1500-2000 pounds per square inch and the solution heated to a temperature of 100 C. When no further hydrogen is taken up by the solution, the Raney nickel catalyst is thereupon removed from the hydrogenated solution as by filtration. The ethanol is evaporated from the hydrogenated solution whereby a solid is obtained. This solid is a hydrogenated condensation product of glucose and octadecylamine. This product predominates in a compound having one amine substituent in its molecule.

Example 6 This example illustrates the synthesis of a 2-ethylhexoic acid salt of a hydrogenated condensation product of lactose and octadecylamine.

80 grams of a hydrogenated condensation product of lactose and octadecylamine, prepared according to the instructions of Example 1, and 30 grams of 2-ethylhexoic acid are admixed and warmed for about 20 minutes over a steam cone. The result is a homogenous liquid product which does not solidify on cooling to room temperature (20 C.). This product consists essentially of a 2-ethylhexoic acid salt of a hydrogenated condensation product of lactose and octadecylamine. 1

Example 8 This example illustrates the synthesis of an oleic acid salt of a hydrogenated condensation reaction product of lactose and octadecylamine.

80 grams of a hydrogenated condensation product of lactose and octadecylamine, prepared according tolthe instructions of Example 1, and 58.8 grams of oleic acid are admixed and warmed for about 20 minutes over a steam come. A homogeneous liquid product is obtained-Which does not solidif on cooling to room temperature (20 C.). This product consists essentially of an oleic acid salt of a hydrogenated condensation reaction product 'of lactose and octadecylamine.

Example 9 This example illustrates the synthesis of an oleic acid dimer salt of a hydrogenated condensation reaction product of lactose and octadecylamine.

80 gramsof a hydogenated, condensation product of lactose and octadecylamine, prepared according to the instructions of Example 1, and 118 grams of an oleic acid dimer (for example, Emery Dimer Acid 3079S) are admixed and warmed for about 20 minutes over a steam cone. A homogeneous liquid product results which does not solidify on cooling. This product consists essentially of an oleic acid dimer salt of a hydrogenated condensation product of lactose and octadecylamine.

Examples. 10-18 These examples illustrate specific fuel oil embodiments of the hydrocarbon fuel composition of this invention.

The formulations of these fuel oil embodiments are as follows:

Example 10: Fuel oil formulation Components: 1 Parts by weight Commercial No. 2 fuel oil 10,000 Hydrogenated condensation product of lactose and octadecenylamine (product of Example 1) V 1 6 Example 11: Fuel oil formulation Components: Parts by weight Commercial No. 2 fuel oil 10,000

Hydrogenated condensation product of lactose and octadecenylamine (product of Example 2) 1 Example 12: Fuel oil formulation Components: Parts by Weight Commercial No. 2 fuel oil 10,000 Hydrogenated condensation product of lactose and dodecylamine (product of Example 3) 1 Example 13: Fuel oil formulation Components: Parts by weight Commercial No. 2 fuel oil 10,000 Hydrogenated condensation product of lactose and N-(higher alkyl) trimethylenediamines (product of Example 4) 1 Example 14: Fuel oil formulation Components: Parts by weight Commercial No. 2 fuel oil 10,000 Hydrogenated condensation product of glucose and octadecylamine (product of Example 5) 1 Example 15: Fuel oil formulation Components: Parts by weight Commercial No. 2 fuel oil 10,000

2-ethylhexoic acid salt of the hydrogenated condensation product of lactose and octadecylamine (product of Example 6) 1 Example 16: Fuel oil formulation Components: Parts by weight Commercial No. 2 fuel oil 10,000 Isobutyn'c acid salt of the hydrogenated condensation product of lactose and octadecylamine (product of Example 7) 1 Example 17: Fuel oil formulation Components: Parts by Weight Commercial No. 2 fuel oil 10,000 Oleic acid salt of the hydrogenated condensation product of lactose and octadecylamine (product of Example 8) 1 Example 18: Fuel oil formulation Components: I Parts by weight Commercial No. 2 fuel oil 10,000 Oleic acid dimer salt of the hydrogenated condensation product of lactose and octadecylamine (product of Example 9) 1 Examples 19-27 These examples illustrate specific jet fuel embodiments of the hydrocarbon fuel composition of this invention.

The formulation of these jet fuel embodiments areas follows:

I Example 19: Jet fuel formulation Components: Concentration JP-5 jet fuel, barrels (U.S.) 1000 Hydrogenated condensation product of lactose and octadecylamine (product of Example 1),pounds 2 7 Example 20: Jet fuel formulation Components: Concentration JP-S jet fuel, barrels (U.S.) 1000 Hyrogenated condensation product of lactose 8 (20 C.). The samples indicated in the following tables as being unoxidized were not so treated. Each sample was then passed through filter paper. The quantity of sludge that was deposited on the filter paper was then judge-d visually for each sample by comparing the filter paper to and N- hi her lk l trimeth lenediamines 5 (Produc(tgfEXa?np)1,e)4) a graded series of standard filter pads ranging in shade f from white to black and rated from 0 to 1 0 with 0 being Example 21: Jet fuel formulation a White pad and 10 being a black Pad Components; concentratign I The results of these tests based on fuel oil A with addi- Kerosene l d barrels 1000 tive concentrations at 0.01% by weight of the fuel 011 are Hydrogenated condensation product of lactose tabulated as followsand octadecylamine (product of Example TABLE I 1), pounds 20 Sam ple No. Additive Example 22: Jet fuel formulation 1 (maximized) None Components: Concentration 3 -g Kerosene blend, barrels 1000 ggfigi g fi g roduct 4 0 Hyrogenated condensation product of lactose otExamile 1. p

and octadecylamine (product of Example 6 g gggig condensatwn Product of Pounds 7 Hrdrogeriatze d condensation'product of 1.0

Example 23: Jet fuel formulation 8 H cir d2 d condensation product of 2.0

Components: Concentration 9 Hydr d g n ted condensation product of 1.5 Kerosene blend, barrels (U'S') 1000 10 Ngii h y d fifg nated condensationproduct 4.5 Hydrogenated condensation product of lactose n or nxam le s. d d t i 1 0 and octadecylamine (product of Example ensa pm 1) pound 1 12 2-EthylhexoicacldsaltofExample6- 1.5 gspbutyrliic zolitd sfag; of Expngple 7. g

'ca 0 xam e Example 24. Jet fuel formulation 15 g (1 Sim. salt Example 9 2. 0 cmgmms M d b 1 (U S) iggg gitiil itli ffiifiiz:

61056116 en arre S aminoe ano Hydrogenated cbndensation product of lactose 19 *amlmfmethylpenmml N-tallow-tr'm th lene diamines rodig EXamP1e14)ePgundS (p No rating of sample 4 was made because the additive was too insoluble to be effective. It will be observed that EXample 251 Jet 1161 fofmulatloll samples 6-9 and 1-15 correspond to the formulations of Components: Concentration pl s 0-18, respectively.

Kerosene blend, barrels 5 00 The results of the tests based on fuel 011 B with additive Hydrogenated condensation product of lactose concentrations at 001% y Weight of the fuel Oil are and dodecylamine (product of Example 3), 40 tabulated as followspounds TABLE II Example 26: Jet fuel formulation sample Additive Rating Components: Concentration fff i jf j: 2:3

Kerosene blend, barrels (U.S.) 1000 3 Octadecylamine H t d ondensation roduct of lucose Lamse yrogena e c P g 5---. Nonhydrogenated condensatlonproduct 4.0 and octadecylamme (product of Example of Example 1. 5) Pounds 6 H%(;l}g)l%2 fd condensation product of 0. 5

1: l t Example 27: Jet fuel formulation 7 figgifi: condensat on pmduc of 0 5 8 Hydrogenated condensation product of 2.0

Components: Concentration Example Kerosene blend 1 (U S 1000 9 iH drogeriatzd condensation product of 1.5

a am e Isobutyric acid salt Of hydrogenated COHdGII 10 Ntfiri hyd foggnated condensationproduct 4.5 Product of lactose and octadecylamme 11 gggf h condensation product f L0 (product of Example 7), pounds 10 Example 5.

The specific jet fuel compositions of these jet fuel formulations of Examples 19-27 are prepared in each case mere- No rating of sample 4 was made because the additive was 1y by adding the hydrogenated condensation product of too insoluble to be effective. In this test series samples 6-9 carboxylic acid salt, as the case may be, to the jet fuel and 11 correspond to the formulations of Examples 10- at room temperature (20-25 C.) and stirring until the 14, respectively. hydrogenated condensation product or carboxylic acid salt The results of the tests based on fuel oil C with additive is dissolved in the jet fuel. concentrations at 0.01% by weight of the fuel oil are The specific fuel oil embodiments of the hydrocarbon set forth in the following Table III. fuel composition of this invention and other fuel oil com- TABLE III positions have actually been tested for inhibition of sludg- S 1 N AMT R t. ing. In the tests No. 2 fuel oils from three commerclal amps We 3 ms sources were employed. They are identified in the followmnoxidized) Nona 2.2 ing tables as 1161 Oils A, B and The tests were as 3:1333133211:II:I:I:'ngnoga at a'eaiacnaiaa'graaaaat 1'0 fOllOWS. xamp c A 350 milliliter sample ofbeach fuel oil 6011;150:3011 ini: iglfifiglfiggiigg gg glgf ggfggff a; dicated in the following ta es was prepare sam- 0 xampe les except those indicated in the tables as unoxidized 7 Oleicamddlmersalt Exampleg were then treated by passing air from a sparger tube through them at 210 F. for 24 hours at a rate of 10 liters V this test series samples 3-7 correspond to the formulaof air per hour, and then cooling to room temperature tlons of Examples 10 and 15-18, respectively.

These data dramatically illustrate the remarkable eflFectiveness of the antisludging additives of this invention in inhibiting sludging of hydrocarbon oils. These data also demonstrate the relative ineffectiveness of reducing sugars generally, of long chain aliphatic amines generally and of the nonhydrogenated condensation products of reducing sugars and long chain aliphatic amines, generally, in inhibiting sludging of hydrocarbon oils.

In these tests it was observed that the antisludging additives of this invention are also of advantage in that they are effective in lessening color formation in hydrocarbon oils under the sort of conditions involved in the oxidation procedure. Moreover, the additives show moderate activity as rust inhibitors.

The specific jet fuel embodiments of the hydrocarbon fuel composition of this invention and jet fuels without additives were also actually tested for sludging. Three jet fuels were employed in these tests. They are identified in the following tables as jet fuels A, B and C. Jet fuel A was a composite of several commerical stable and unstable JP- fuels. Jet fuel B was a composite of several stable and unstable kerosene blends employed in commercial jet fuels. Jet fuel C was similar to jet fuel B except that it contained a higher percentage of unstable fuels than did jet fuel B. The test procedure employed in these tests is as follows.

CFR fuel coker test A discussion of this test is given by Crampton et al. in a paper entitled Thermal Stability-A New Frontier for Jet Fuel, at the SAE summer meeting in 1955. Instructions for operating the CFR Fuel Coker are contained in Manual No. 3 of the Coordinating Research Council, Inc.

A 5 gallon sample of the fuel is placed in a reservoir and a small quantity of air is bubbled through the sample. Then, the aerated fuel is pumped at a pressure of 150 pounds per square inch and a flow rate of 46 pounds per hour through the preheater assembly and then through the furnace assembly of the CFR Fuel Coker. The Furnace assembly contains a micron, sintered, stainless steel filter. The preheater assembly and furnace sections of the CFR Fuel Coker simulate a heat exchanger and jet engine burner nozzle opening, respectively. As the fuel passes through the preheater assembly it is heated thereby to a temperature, for example, in the range of about 300-400 F. and as it passes through the furnace section it is heated to a temperature, for example, in a range of about 400-500 F. Under these conditions, fuel degradation products deposit in the preheater assembly and are trapped on the furnace filter, thereby causing a pressure drop on the mercury manometer connected across the filter. Usually, the test is run until a pressure drop of inches of mercury is indicated on the manometer, or for 300 minutes, whichever occurs first.

Fuel stability under this test is expressed in goodness units. These units are a measure of time required for the pressure drop to reach 25 inches of mercury or of the actual pressure drop if less than 25 inches of mercury, at 300 minutes. The ratings range from 0 for immediate clogging of the filter to 900 for no manometer pressure drop at 300 minutes.

It is generally considered that fuel is stable to practical degree when it does not cause a pressure drop across the filter of the CFR Fuel Coker greater than 10 inches of mercury in 300 minutes.

Test results, additives and additive concentrations in the first series of actual tests involving compositions of this invention are set out in the following Table IV. In

these tests, the CFR Fuel Coker conditions were:

Fuel pressure p.s.i 150 Fuel flow rate lb./hr 6 Preheater temperature F 400 Filter temperature F 500 TABLE IV Concentration [pounds per 1,000 Good- Sample Jet barrels ness No. fuel Additive (U.S.)] rating 1 A None None 379 2 A Hydrogenated condensa- 643 tiion product of Example 3 A Hydrogenated condensa- 5 778 tiion product of Example 4 B Nohe None 5 B Hydrogenated condensa- 20 890 glen product of Example :do 2 890 do 1 598 Hydrogenated condensa- 800 tion product of Example Hydrogenated condensa- 5 295 ztxion product of Example None None 98 Hydrogenated condensa- 10 900 gion product of Example Isobutyric acid salt 0 10 900 Example 7.

In these tests samples 2-3, 5-9 and 1l-12 correspond to the formulations of Examples 19-27, respectively.

These data likewise dramatically illustrate the remarkable efiectiveness of the specific antisludging additives of this invention in inhibiting sluding of jet fuels, particularly at temperatures of 400500 F.

Thus, this invention provides a hydrocarbon fuel composition characterized by a high degree of protection relative to sludging even at temperatures up to about 500 F.

An advantage of this invention is that it now makes available for jet engine use hydrocarbon fuels which othewise are too unstable for this use.

Other features, advantages and embodiments of this invention will be readily apparent to those in the exercise of ordinary skill in the art after reading the foregoing disclosure. In this regard, while this invention has been described in considerable detail relative to specific embodiments thereof, variations and modifications of these embodiments can be effected within the spirit and scope of the invention as described and claimed.

The embodiments of the invention in which an exclusive property of privilege is claimed are defined as follows:

1. A sludging inhibited fuel composition which comprises:

(A) a liquid hydrocarbon fuel which is subject to sludging, and (B) an additive selected from the group consisting of;

(l) a mixture of hydrogenated condensation products of (a) reducing sugars selected from the group consisting of lactose, glucose, maltose, cellobiose, galactose and mannose, and (b) at least one aliphatic hydrocarbon amine having 8 to 22 carbon atoms; and (2) carboxylic acid salts of said hydrogenated condensation products derived from carboxylic acids of aliphatic and aromatic hydrocarbons having 4 to 20 carbon atoms,

said additive being present at a concentration to substantially inhibit sludging of said hydrocarbon fuel.

2. A sludging inhibited fuel composition according to claim 1 wherein said additive is present at a concentration in the range of about 0.0005 to 0.05% by weight of said liquid hydrocarbon fuel.

3. A sludging inhibited fuel composition according to claim- 2 wherein said additive is a mixture of hydrogenated condensation products.

4. A sludging inhibited fuel composition according to claim 3 wherein said mixture of hydrogenated condensation products is derived from lactose and at least one aliphatic hydrocarbon amine having 8 to 22 carbon atoms.

5 A sludging inhibited fuel composition according to claim 3 wherein said mixture of hydrogenated condensation products is derived from glucose and at least one aliphatic hydrocarbon amine having 8 to 22 carbon atoms. 6. A sludging inhibited fuel composition according to claim 2 wherein said additive is selected as the carboxylic acid salts of said mixture of hydrogenated condensation products.

7. A sludging inhibited fuel composition according to claim 6 wherein said carboxylic acid salts of said mixture of hydrogenated condensation products are derived from a carboxylic acid selected from the group consisting of isobutyric acid, 2-ethylhexanoic acid, lauric acid, oleic acid, stearic acid and naphthoic acid.

12 7 References Cited UNITED STATES PATENTS 2,805,135 9/1957 Bell et a1. 44-66 2,891,052 6/1959 Boettner ct a1. 360-211 1/ 1960 Lindstrom et a1 4466 FOREIGN PATENTS 745,036 1/1956 England.

10 DANIEL E. WYMAN, Primary Examiner.

Y. H. SMITH, Assistant Examiner.

Us. 01. .X.R. 

